We are reading the performance data from a table for different releases and creating a line graph to compare different release performance metrics. When the app runs locally, Callbacks fire as they should (on page load), and the app is usable. However, when the app is deployed to a UNIX server the callbacks stop working.
Error: Callback failed: the server did not respond.
at http://server_ip:port/_dash-component-suites/dash_renderer/dash_renderer.v1_5_1m1593111735.dev.js:33217:11
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I'm developing an app that uses Bluetooth to communicate with Smart Devices.
It needs to authorise iPhone with such scheme:
Scanning devices with some filters of services UUIDs
Connecting to a device, discovering services, discovering characteristics
Calling read operation to retrieve public keys
Exchange received public keys (using ECDH)
Generate token
Write encrypted token (using AES) to device using writeValue
That's all, after that I have stable connection and able to interact with my Smart Device (writing values to protected properties).
The question is that when I restart my app and do all of the steps above, except Step_5 (because I have my token generated and validated previous time), on Step_6 delegate method didWriteValueFor: doesn't even get called, instead of this delegate method didDisconnectPeripheral being called with Error Domain=CBErrorDomain Code=0 "Unknown error." UserInfo={NSLocalizedDescription=Unknown error.} and I can't write values to protected characteristics.
I can't get what I'm doing wrong. Any help would be nice.
UPD[0]: Sometimes I can get a callback for didWriteValueFor: on Step_6 but IMMEDIATELY (like less than a 0.5 sec) iPhone is being disconnected with an error from above.
UPD[1]: Also I was trying to cancelPeripheralConnection() before closing my app because Smart Device does not handle multiple connections in hardware reasons, but no luck here.
UPD[2]: Well, after three days of searching for information, I realized that I was digging in the wrong direction at all. The problem was that I interrupted the application with the “Stop” button in Xcode, and didn’t close it manually via iPhone, therefore, willTerminate was not called, and even if it was called, it had a very limited amount of time to execute all the processes that were supposed to be executed, as a result, the connection didn’t interrupt (the cancelPeripheralConnection method was not called), and the next time I started the App, I tried to establish a connection with a device that already has a connection to my App.
At least it started connecting often, but I'm still getting this error sometimes. The main question is: how properly disconnect from the device? For now I’m unsubscribing from all the properties that have isNotify: true (setting to false) and call cancelPeripheralConnection. Do I need to wait the “unsubscribe” process before disconnecting?
UPD[3]: It doesn't matter if I wait for unsubscribe finished or not. At least it have no effect.
Well, I found the reason why disconnects are appears:
Since Smart Device has several characteristics of public keys that need to be read, encrypted and then sent back, the order keys I read and write was important. Since writeValue and readValue are asynchronous, my order went astray. As soon as I began to keep order, everything worked like a clock.
I am using WinHTTP 5.1 in one of my Delphi FMX application which connects to REST servers in parallel.
There are lot of GET and POST which are called continuously by the client.
I have observed that after say 200-300 GET commands below method is becoming extremely slow:
WinHTTPRequest.Open(FURL, FDocument, True)
The credentials are set properly and i can observe on Wireshark that the Open method is taking approx a minute to execute as after open i am calling Send :
WinHTTPRequest.Send
Any advises ?
I implemented an UWP Server Socket following the sample here and it correctly works.
Now I want to make the app able to continuously accept requests, but I expect that when the app is suspendeded and a client sends a request, the server is not able to respond. If I am correct, what is the best way to avoid this status change? If possible, I would prefer a solution with Extended Execution instead of implementing a Background Task, but I don't know if the following code in the OnSuspending method is enough to keep the app in the Running status:
var newSession = new ExtendedExecutionSession();
newSession.Reason = ExtendedExecutionReason.Unspecified;
newSession.Revoked += SessionRevoked;
I saw people calling a "LongRunningWork()" function in other samples, but in my case the code to execute is already defined in the code-behind of the view as shown in the link above, so I would like simply keeping the app always running. Keep in mind that it is a LOB application, so I don't have Store limits.
I have an application in Asp.net MVC where at some point I would like to display a modal dialog to the user that would display process execution progress indicator.
The process behind the scenes does a lot of database data processing (based on existing data it generates lots of resulting records that get written back to database as well). Process may take anything from a brief moment to a very long time (depending on existing data).
Application will initiate this process asynchronously (via Ajax request) and display progress in the same manner.
The problem
I've read a bit about Async controllers where one can asynchronously start a process and will informed about the end of it but there's no progress indication and I'm not really sure how browser timeouts are handled. As far as the client goes an async request is the same as synchronous one. Client will therefore wait for response (as I understand it). the main difference being that server will execute something in async manner so it won't block other incoming requests. What I should actually do is:
make a request that would start the process and respond to the client taht process has started.
client would them periodically poll the server for process progress status getting immediate response back with percentage value (probably as JSON)
when progress would be 100% it would mean that it ended so client would know to make a request for results.
I'm not convinced that async controllers work this way...
The thing is that I'm not really sure I understand async controllers hence am not sure which approach should I use approach this problem as just described? I see two possibilities myself:
Asp.net MVC Async controllers if they can work this way
Windows Service app that processes data on request and reports its progress - this service would be started by writing a particular record to DB using a normal controller action; that would start it and then service would be writing its progress status to DB so my Asp.net MVC app would be able to read it on client process polling requests.
I haven't used Asynch controllers myself in a project. However here's a link to someone who has.
asynchronous-processing-in-asp-net-mvc-with-ajax-progress-bar
I have personally used Number 2 in a large production project.
Number 2 was a Service App running on a separate server using OpenSSH to communicate between the two servers. We'd poll for progress periodically to update the progress bar to the clients UI via AJAX.
Additionally by separating your web server from your long running process you are separating your concerns. You web server is not interested in writing files to disk, handling IO, etc and so shouldn't be burdended with such.
If your long running process has to be killed or fails then this wont affect your web server handling requests, and processing transactions.
Another suggestion would be for an extremely long running process is not to burden the client with waiting, give them an option to come back later to see the progress. I.e. send them an e-mail when its done.
Or actually show them something interesting, in our case we had a signed Java Applet show exactly what their process is doing at that exact moment.
Am new to android, am developing application with websevices using json parsing with httpget method,cant use http post method in android actually.
It working fine normally, but many time it shows the error on emulator like activity not responding force close activity.when i put that url in browser it shows the result .but i don't know why this activity not responding error came.
I think the httprequest took more time to retrieve the data from server,but am not sure. any one help me to how to avoid this error or how to minimize this .
I want know what are the possibilities to get this activity not responding error.
Thanks,
Lakshmanan
You need to perform blocking operations such as I/O in a separate thread - see the below linked resource:
http://developer.android.com/guide/practices/design/responsiveness.html:
In Android, the system guards against applications that are insufficiently responsive for a period of time by displaying a dialog to the user, called the Application Not Responding (ANR) dialog, shown at right in Figure 1. The user can choose to let the application continue, but the user won't appreciate having to act on this dialog every time he or she uses your application. It's critical to design responsiveness into your application, so that the system never has cause to display an ANR dialog to the user.
To avoid ANR (Application Not Responding) dialog,
Your business logic code is inside doBackground() of AsyncTask and You may also need to override onPostExecute(),etc. After that it is better to invoke the async task in a Service (bound or normal service).
Service:
(bound service or normal service based on your requirement)
From, android office documentation:
A service is "bound" when an application component binds to it by calling bindService(). A bound service offers a client-server interface that allows components to interact with the service, send requests, get results, and even do so across processes with interprocess communication (IPC). A bound service runs only as long as another application component is bound to it. Multiple components can bind to the service at once, but when all of them unbind, the service is destroyed.